The development of the nano-science nowadays has been extensively applied in a variety of fields, especially in the semiconductor industry, which constantly produces many nano-devices and nano-components, wherein, the nano-ring structure is always used in semiconductor memory (DRAM or SRAM) or hard disk. The number and density of the nano-ring structure in unit area or unit volume will directly affect the memory capacity, quality or performance. Accordingly, the fabricating methods of nano-ring structure, which are disclosed recently such as USA patents in U.S. Pat. No. 6,863,943, U.S. Pat. No. 6,906,369, U.S. Pat. No. 7,002,839 and the like, all address and effort on the issue of number and density of the nano-ring structure in unit area or unit volume though minor differences exist among each other.
As shown in FIGS. 1 through 3c, the nano-structure is produced from conventional nano-lithography. The fabricating steps are as below: (A): Firstly, layout the expected nano pattern Q on a photomask M, then put said photomask M on the top surface of a substrate 1, which is spread with photo-resist 2 (as shown in the FIG. 1); (B): Secondly, pass light beam e through said nano pattern Q on said photomask M so as to have same pattern as said nano pattern Q on said photo-resist 2, which spreads on said substrate 1, by exposure and development to define a nano-aperture 3 structure (as shown in the FIG. 2); (C): Thirdly, by means of a deposit source device 100, directly a deposit material B of gas molecule or atom state on the surroundings and bottom of said nano-aperture 3 (as shown in the FIGS. 3a and 3b); and (D): Finally, selectively remove said photo-resist 2 by solution, thereby forming a nano quantum dot 4 structure on the surface of said substrate 1 (as shown in the FIG. 3c).
The conventional process aforesaid is confined to the precision limit of the existing photolithography such that the current best precise nano-scale can only reach 60˜65 nm; Hence, the nano-scale of said nano-aperture 3 from photomask M of pattern transferring photolithography is over 60 nm; Thereby, the nano-scale of said nano quantum dot 4 fabricated from these equipment is also over 60 nm relatively; Thus, the physical size limit of said conventional nano-devices of nano-structure are still in the range of over 60 nm; Therefore, how to breakthrough this bottleneck such that making the nano-scale of nano-aperture 3 be smaller becomes the impending crucial technical tough question of all experts in various fields; The solution being subject to the industrial practical feasibility in mass production and cost-effective economical principle so that the choice of means in technical breakthrough becomes more difficult; The scientists who understand the nano-science and the experts who familiarize with nano-technology are all aware of the benefits of working out the nano-ring structure being smaller than 50 nm or even 1˜2 nm, but none of better solution or effective technical breakthrough is proposed, announced or applied.